Dear Claudia, Here are a few thoughts as I'm off for a couple of weeks off from Thursday this week. We can go with a proposal that is more of the same - more D&A studies with more variables globally and some getting down to regional scales. My weekend thoughts were that we could structure the proposal a little differently to try and explain more why temperature seems to work well, but variables like precipitation and pressure require GCM and RCM output to be scaled. D&A work began with temperature using monthly gridded datasets at as near to global scales as obs data allows. We've gone down to the daily time scale with precipitation and temperature extremes and also gone down to regional space scales for specific events (like the 2003 European Heat Wave). It is at these regional scales that most people would like to see AGW explanations of recent changes. It is at these finer temporal and spatial scales that we need to emphasize in the proposal - something that is already there in the proposal outline. Reducing the temporal scale to daily limits us due to data availability, except for some long daily series in a few areas. My thought is that we need to try to also explain why AGW runs underestimate things for variables like precipitation and pressure. For precipitation, there are two aspects - the amounts and also the number of raindays. Monthly gridded precipitation datasets have also been developed for raindays, so it's possible to also look at amounts per event. Models probably don't do raindays that well, and there will be issues of comparing point values which are gridded to boxes, while models do these areas directly. There are also issues of what threshold for a rainday to use. It would also be possible to look at how the parameters of say the Gamma Distribution are changing and whether models reproduce these well or not. In CRU, we have gridded PDSI series available and a paper soon to be submitted. This uses a different formulation for the potential evapotranspiration (than the traditional Thornthwaite) but it doesn't seem to make much difference to first few PCs. So, I'm suggesting two work tasks, which would be at both the global land scale and also at the regional land scale. Using D&A with PDSI. There is quite a bit of number crunching here to get Penman PET from GCM and RCM output. It's a bit of a hobby horse of mine to get modellers to output PET, as it is so useful for impacts people. Using D&A with parameters from the precipitation distribution (mainly monthly, but daily would be possible where datasets are good enough). I can sketch out some text for these two, if they are considered useful, and there is a limit of how much text each sub task requires - I guess not much else the proposal would get too long. As for the tasks and sub-tasks already there, I'd like to be involved in the one numbered 1.4 and also the one with Gabi on regional variability over the last millennium (which is probably just Europe and North America). 1.4 requires these noise-reduction techniques (taking out ENSO, volcanoes and circulation influences a la Dave Thompson) to be applied to GCMs as well. Worth trying at the global and hemispheric scale first. I'm not saying we shouldn't continue to go down the operational D&A route, but we do try and need to explain why temperature works well on all space and temporal scales but precip and pressure require considerable scaling. I've no ideas on what to do about pressure. Cheers Phil At 11:46 04/08/2009, Stott, Peter wrote:

Dear Claudia, I'm off on vacation tomorrow and therefore somewhat stretched for a very considered response from me - sorry - but the items I have my name against look fine to me. There are a couple of items I couldn't find which we could offer something up if we think appropriate - attribution of ocean changes including temperature, salinity and sea level rise to include new datasets, model analyses and methodologies (could include Ben, Tim, Peter, ...) to answer questions such as can we close sea level budget, can we better determine planetary radiative imbalance ... - hydrological cycle changes using new techniques, datasets (eg salinity in addition to ocean analyses if we can use them), models etc to attribute greenhouse gas and aerosols on hydrological cycle changes and determine whether (as has been suggested) models generally underestimate observed hydrological cycle changes, both means and extremes (could include Myles, Peter, Francis ? ...) I liked the "Critical review of methods used for proposed operational attribution programmes." bullet. I think it would be good if IDAG could provide an assessment of proposed methodologies and what would need to be done/satisfied for output to be reliable, robust and timely. Along these lines we have planned a BAMS paper which I was in line to lead. This might takes us a bit of the way if we can get the people involved in this development actively engaged in such a paper. Right now a many-author many-viewpoint BAMS paper sounds a bit of a daunting prospect but maybe it will seem more achievable after a break. Finally I've attached the WIRE article I submitted yesterday by Stott, Gillett, Hegerl, Karoly, Stone, Zhang, Zwiers (form some reason the submission page only allowed me to enter 2 names in the relevant field, hence only the first two appear on the covering page). This is one of IDAG's paper deliverables I think (?). All the best with getting the proposal off, Peter Dr. Peter Stott Head, Climate Monitoring and Attribution, Met Office Hadley Centre, Fitzroy Road, Exeter. EX1 3PB, UK Tel +44(0)1392 886646 Fax +44(0)1392885681 Email: peter.stottatXYZxyzoffice.gov.uk [1]http://www.metoffice.gov.uk -----Original Message----- From: claudia.tebaldiatXYZxyzil.com [[2]mailto:claudia.tebaldiatXYZxyzil.com] On Behalf Of claudia tebaldi Sent: 31 July 2009 19:51 To: Myles Allen; Knutti Reto; Stott, Peter; Gabi Hegerl; Zwiers,Francis [Ontario]; Tim Barnett; Hans von Storch; Phil Jones; David Karoly; Toru Nozawa; Ben Santer; Daithi Stone; Richard Smith; Nathan Gillett; Michael Wehner; Doug Nychka; Xuebin Zhang; Tom Knutson; Tim Delsole; Jones, Gareth S (Climate Scientist); Stephen Leroy; seung-ki.minatXYZxyzgc.ca Subject: Proposal as it stands -- now I need your help! Dear all please find attached the current version of the IDAG proposal. Please disregard the format of the reference list for now, I'm going to work on the cosmetics later (but feel free to add to that as you see fit). I wish I knew exactly when the deadline for submitting this was, but meanwhile, could I ask you for some specific input and some more general feedback at your earliest convenience, and please *****no later than August 20th?***** Here at first is a specific list : 1) Those of you in charge of the specific tasks that were highlighted at the meeting (you know who you are) could you please look at the task/subtask list and clean it up/flesh it out/make it a little more coherent? Add or take out as you see fit! 2) All of you: could you sign up for specific subtasks and give me an idea of a 3-yr timeline for these activities that you would like to follow? Please iterate with the heads of the task for this if you need to work something out... 3) All of you fully funded, please send me a brief bio-sketch -- and whatever you gave Gabi in the past in terms of financial information for the funds you need, could you please send it on to me, updated? Then a more general list: I would REALLY REALLY appreciate it if you all read the 'thing' and made comments/added/corrected as you see fit (of course with track changes on!). I rather have too much and work on shedding than have gaping holes in this narrative. Everybody that recognizes his/her work in the Scientific background section: would you please paste in a figure (and a description) to make this think less black and white? I hope this is not too much to ask on this fairly short timeline, I really need some help here at this point. And help means both addition to and refurbishing of what's in there but also checks and, by all means, corrections. Thank you very much in advance, and please let me have something within the deadline!!! Hope you are all having a good summer (and this does not spoil it!) best to all claudia -- Claudia Tebaldi Research Scientist, Climate Central [3]http://www.climatecentral.org currently visiting Stanford University, Department of Statistics tel. 650 796 6974 cell 303 775 5365